1. Field of the Invention
The present invention relates to a method of coating a permeable web, such as a textile, a fibrous fleece or a similar substratum having an open structure with a viscous substance, while using at least one combination consisting of a rotatable cylindrical screen with a support roller, between which the substratum to be coated is passed, the interior of said screen being provided with means such as a squeegee, for pressing the substance through the perforations of the screen.
The object of such a method is to obtain a textile material which, in view of the properties desired or the improvement thereof, is provided on one or both sides with a single or several layers of coating. The textile substratum ensures the flexibility required for the final product and often serves for absorbing the mechanical stress exerted thereon. The substratum may consist of a woven fabric, a knitted material, a fibrous fleece etc., the weight and permeability of the substratum being allowed to vary within wide limits.
2. Description of the Prior Art
In the prior art methods have been used which are known in practice as "knife-coating, reverse-roll coating" (see Netherlands Patent Application No. 70,06063), while a process called dip coating is referred to as well.
These known methods cannot be controlled sufficiently for obtaining a reliable and reproducible process realizing a constant quality of the final product, as in such a case it is an important drawback that the amount of substance applied cannot be controlled independently with regard to the degree of penetration into the substratum. Attempts have been made to solve the latter problems in a system according to Netherlands Patent Application No. 71,01419.